Early-detection and elimination of food-borne bacteria is essential for extending retailer shelf life and preventing consumer impact. Spectroscopic devices for determining the freshness of meat by relying on the fluorescent properties of bacteria species are known. In such devices, a sample is typically exposed to a light signal having a certain excitation wavelength, and a light detector detects emitted light of a longer wavelength (fluorescence) from the sample to identify the presence of bacteria. Spectroscopy is often real time, non invasive, non-destructive and non-chemical. Through careful examinations of excitation and emission spectra of bacteria one can construct ‘fingerprints’ for bacterial species detection and identification. It is also possible to estimate the level of bacterial contamination as the emission intensity is proportional to the bacterial concentration.
Known bacteria detection devices utilise narrowband filters to isolate and analyse the fingerprint wavelengths in the emitted signal. Narrowband filters are generally more expensive and have a larger attenuation factor than their long pass counterpart.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide a spectroscopic method, system or device for detection of bacteria that goes in some way towards alleviating some of the disadvantages of known devices as listed above, or to at least provide the public with a useful choice.